JPWO2015146761A1 - Stirling refrigerator - Google Patents

Abstract

In the Stirling refrigerator, the displacer 22 has an internal space filled with gas. The expander body 20 accommodates the displacer 22 so as to be able to reciprocate. The displacer 22 accommodates in the internal space one or more convection suppression plates 42 that suppress gas convection. The convection suppression plate is disposed in a direction crossing the longitudinal axis of the displacer. The regenerator 38 may be provided in the expander main body 20 so as to be located in a predetermined cylindrical region having the longitudinal axis of the displacer 22 as a central axis in the outer peripheral portion of the displacer 22. Even if the displacer 22 reciprocates, the convection suppression plate 42 may be provided so as to be in a position corresponding to a predetermined region where the regenerator 38 is located.

Description

  The present invention relates to a refrigerator, and more particularly to a Stirling refrigerator.

  With respect to a Stirling refrigerator, the displacer may be hollow to contain gas. At this time, it is known that heat loss occurs due to heat transfer by convection of gas in the displacer. For this reason, in order to regulate the convection of gas, the technique which accommodates cotton-like, strip | belt-shaped, and powder-like heat insulating material in a displacer is known (for example, refer patent document 1).

JP 2004-3436 A

  One exemplary object of an aspect of the present invention is to provide a technique for more appropriately suppressing gas convection in a displacer.

  In order to solve the above-described problems, a Stirling refrigerator according to an aspect of the present invention includes a displacer having an internal space filled with gas, and an expander body that accommodates the displacer so as to reciprocate. The displacer accommodates in the internal space one or more convection suppression plates that suppress gas convection, and the convection suppression plates are arranged in a direction that intersects the longitudinal axis of the displacer.

  Note that any combination of the above-described constituent elements and the constituent elements and expressions of the present invention replaced with each other among methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which suppresses the convection of the gas in a displacer more appropriately can be provided.

1 is a diagram schematically showing a Stirling refrigerator according to an embodiment of the present invention. It is a figure which shows roughly the expander of the Stirling refrigerator which concerns on one embodiment of this invention. Drawing 3 (a)-(b) is a figure showing typically an example of the accommodation position of the convection control board concerning an embodiment. It is a schematic diagram which shows the internal structure of the displacer which concerns on another embodiment. It is a figure which shows roughly the expander of the Stirling refrigerator which concerns on one embodiment of this invention. It is a figure which shows roughly the expander of the Stirling refrigerator which concerns on one embodiment of this invention. It is a figure which shows roughly the expander of the Stirling refrigerator which concerns on one embodiment of this invention.

  The displacer reciprocates during operation of the Stirling refrigerator. For this reason, when using the member which controls the convection of gas in a displacer, it is desirable to be fixed to the displacer. However, when, for example, a cotton-like, belt-like, or powder-like heat insulating material is used as a member for regulating gas convection, it is considered difficult to fix these members in the displacer. If the member that regulates the convection of the gas cannot be fixed to the displacer, the convection of the gas in the displacer may not be properly regulated. In some cases, when the displacer moves back and forth, a member that restricts convection may collide with the inner wall of the displacer, or members that restrict convection may collide with each other, which may cause abnormal noise. Therefore, a Stirling refrigerator according to an embodiment of the present invention uses a plate-like member as a member for regulating gas convection.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. Moreover, the structure described below is an illustration and does not limit the scope of the present invention at all.

  FIG. 1 is a diagram schematically showing a Stirling refrigerator 10 according to an embodiment of the present invention. The Stirling refrigerator 10 includes a compressor 11, a connecting pipe 12, and an expander 13.

  The compressor 11 includes a compressor case 14. The compressor case 14 is a pressure vessel configured to hold a high-pressure working gas in an airtight manner. The working gas is, for example, helium gas. The compressor 11 includes a compressor unit that is accommodated in the compressor case 14. The compressor unit includes a compressor piston and a compressor cylinder, one of which is a movable member 15 configured to reciprocate in the compressor case 14 and the other is fixed to the compressor case 14. It is a stationary member. The compressor unit includes a drive source for moving the movable member 15 relative to the compressor case 14 in a direction along the central axis of the movable member 15. The compressor 11 includes a support portion 16 that supports the movable member 15 on the compressor case 14 so that the movable member 15 can reciprocate. The movable member 15 vibrates with respect to the compressor case 14 and the stationary member with a certain amplitude and frequency. The volume of the working gas in the compressor 11 also vibrates with a specific amplitude and frequency.

  A working gas chamber is formed between the compressor piston and the compressor cylinder. This working gas chamber is connected to one end of the connection pipe 12 through a communication passage formed in the stationary member and the compressor case 14 described above. The other end of the connection pipe 12 is connected to the working gas chamber of the expander 13. In this way, the working gas chamber of the compressor 11 is connected to the working gas chamber of the expander 13 by the connection pipe 12.

  As will be described later with reference to FIG. 2, the expander 13 includes an expander body 20, a displacer 22, and a support unit 40.

  FIG. 2 is a diagram schematically showing an expander 13 according to an embodiment of the present invention. FIG. 2 shows an outline of the internal structure of the expander 13.

  The expander 13 includes an expander body 20 and a displacer 22. The expander body 20 is a pressure vessel configured to hold a high-pressure working gas in an airtight manner. The displacer 22 is a movable member configured to reciprocate within the expander body 20. The expander 13 includes at least one support portion 40 that supports the displacer 22 on the expander body 20 so that the displacer 22 can reciprocate.

  The expander body 20 includes a first section 24 and a second section 26. The first compartment 24 includes a working gas expansion space 28 formed between the expander body 20 and the displacer 22. A portion of the expander body 20 adjacent to the expansion space 28 is provided with a cooling stage 29 for cooling the object. The second section 26 is configured to support the displacer 22 on the expander body 20 via the elastic member 30.

  The second section 26 is adjacent to the first section 24 in the reciprocating direction of the displacer 22 (indicated by an arrow C in the figure). A seal portion 25 is provided between the second compartment 26 and the first compartment 24, whereby the second compartment 26 is partitioned from the first compartment 24. Therefore, the pressure fluctuation of the working gas in the first section 24 is not transmitted to the second section 26 or does not significantly affect the pressure of the working gas in the second section 26. The second compartment 26 is filled with the same type of gas as the working gas so as to have a pressure equivalent to the average pressure of the working gas sent from the compressor 11.

  The displacer 22 includes a displacer main body 32 accommodated in the first section 24 and a displacer rod 34. The displacer rod 34 is a shaft portion that is thinner than the displacer main body 32. The displacer 22 has a central axis that is parallel to the reciprocating direction thereof, and the displacer main body 32 and the displacer rod 34 are provided coaxially with the central axis of the displacer 22. The displacer 22 has an internal space and is filled with the same kind of gas as the working gas. The displacer 22 includes one or more convection suppression plates 42 that suppress convection of gas. Details of the displacer 22 will be described later.

  The displacer rod 34 extends from the displacer body 32 through the seal portion 25 to the second compartment 26. The displacer rod 34 is supported by the expander body 20 in the second section 26 so that the displacer 22 can reciprocate. For example, the seal portion 25 described above may be a rod seal formed between the displacer rod 34 and the expander body 20.

  The first section 24 forms a cylinder portion that surrounds the displacer body 32. An expansion space 28 is formed between the bottom surface of the cylinder portion and the end surface of the displacer main body 32. The expansion space 28 is formed on the side opposite to the joint portion between the displacer main body 32 and the displacer rod 34 in the reciprocating movement direction of the displacer 22. A gas space 36 connected to the connection pipe 12 is formed between the joint portion and the seal portion 25.

  A regenerator 38 is attached to the side surface of the cylinder portion of the expander body 20 so as to be positioned on the outer peripheral portion of the displacer body 32. More specifically, the regenerator 38 is provided on the side surface of the cylinder portion of the expander main body 20 so as to be positioned in a cylindrical region having the longitudinal axis of the displacer 22 as a central axis in the outer peripheral portion of the displacer main body 32. . For example, the regenerator 38 has a laminated structure of wire mesh. The working gas can be circulated between the expansion space 28 and the gas space 36 through a regenerator 38.

  A water-cooled heat exchanger 37 is provided between the regenerator 38 and the gas space 36. The water-cooled heat exchanger 37 cools the working gas supplied from the compressor 11 and realizes heat exchange for releasing the heat to the outside of the expander 13. A low-temperature heat exchanger 39 is attached between the regenerator 38 and the cooling stage 29.

  The expander 13 supports the displacer 22 on the expander body 20 so that the displacer 22 can reciprocate at a plurality of different positions in the reciprocating direction of the displacer 22. For this purpose, the expander 13 includes two support portions 40. These two support portions 40 are provided in the second section 26. In this way, tilting of the displacer 22 with respect to the central axis can be suppressed.

  The support unit 40 includes the elastic member 30 described above. The elastic member 30 is disposed between the displacer rod 34 and the expander body 20 so that an elastic restoring force acts on the displacer 22 when the displacer 22 is displaced from the neutral position. As a result, the displacer 22 reciprocates at a natural frequency determined from the spring constant of the elastic member 30, the spring constant resulting from the pressure of the working gas, and the mass of the displacer 22. The displacer rod 34 is fixed to the elastic member 30 via the elastic member mounting portion 51.

  The elastic member 30 includes, for example, a spring mechanism including at least one leaf spring. The leaf spring is a spring also called a flexure spring, and is flexible in the reciprocating direction of the displacer 22 and rigid in the direction perpendicular to the reciprocating direction. Such a leaf spring is disclosed in, for example, Japanese Patent Application Laid-Open No. 2008-215440. This document is incorporated herein by reference in its entirety. Therefore, the displacer 22 is allowed to move in the direction along the central axis by the elastic member 30, but the movement in the direction orthogonal to the displacer 22 is restricted.

  In this way, a vibration system including the displacer 22 and the elastic member 30 is configured. This vibration system is configured such that the displacer 22 vibrates at the same frequency as the vibration of the movable member 15 of the compressor 11 and has a phase difference with the vibration. The displacer 22 is driven by the pulsation of the working gas pressure generated by the vibration of the movable member 15 of the compressor 11. A reciprocating motion of the displacer 22 and the movable member 15 of the compressor 11 forms a reverse Stirling cycle between the expansion space 28 and the working gas chamber of the compressor 11. Thus, the cooling stage adjacent to the expansion space 28 is cooled, and the Stirling refrigerator 10 can cool the object.

  Next, the displacer 22 will be described in more detail.

  As described above, the displacer 22 according to the embodiment is hollow and has an internal space filled with the same kind of gas as the working gas. By making the displacer 22 hollow, the displacer 22 is reduced in weight, which also contributes to reducing the weight of the Stirling refrigerator 10 itself. Further, the internal space of the displacer 22 is filled with the same kind of gas as the working gas. Even if the gas inside the displacer 22 flows out to the first compartment 24 or the second compartment 26 for some reason, the working gas is contaminated thereby. This is because it can be prevented.

  Here, it is possible to prevent the gas inside the displacer 22 from flowing into the first compartment 24 or the second compartment 26 by evacuating the internal space of the displacer 22. In this case, if the internal space of the displacer 22 and the first compartment 24 or the second compartment 26 are electrically connected for some reason, the working gas flows into the internal space of the displacer 22 and the working gas contributing to cooling decreases. From the above, it is preferable that the same type of gas as the working gas fills the internal space of the displacer 22.

  The cold generated in the expansion space 28 is stored in the regenerator 38. For this reason, in the regenerator 38, the end portion on the side in thermal contact with the low-temperature heat exchanger 39 has a lower temperature than the end portion on the side in thermal contact with the water-cooled heat exchanger 37. Hereinafter, in the present specification, the end of the regenerator 38 on the side that is in thermal contact with the low-temperature heat exchanger 39 is referred to as “low-temperature end”, and the end on the side that is in thermal contact with the water-cooled heat exchanger 37 is referred to as “ "High temperature end". Similarly, in the displacer 22, a distal end portion facing the expansion space 28 is described as a “low temperature end”, and a proximal end portion facing the gas space 36 (that is, the compression space) is described as a “high temperature end”.

  During the operation of the Stirling refrigerator 10, a temperature gradient is generated in the regenerator 38 in which the temperature decreases from the high temperature end toward the low temperature end. As shown in FIG. 2, the regenerator 38 is provided in the expander body 20 so as to be located in a cylindrical region having the longitudinal axis of the displacer 22 as a central axis in the outer peripheral portion of the displacer 22. Further, the range of reciprocation of the displacer 22, that is, the stroke length of the displacer 22 is shorter than that of the regenerator 38. For this reason, the displacer 22 has a region that contacts the vicinity of the low temperature end of the regenerator 38 and a region that contacts the vicinity of the high temperature end of the regenerator 38. For convenience of explanation below, the position of the displacer 22 that is in thermal contact with the regenerator 38 may be referred to as a “position corresponding to the regenerator 38”. The “position corresponding to the regenerator 38” can also be expressed as “a position facing the regenerator 38” in the displacer 22.

  As a result, the gas filling the inner space of the displacer 22 also has a temperature difference between the gas existing on the low temperature end side of the displacer 22 and the gas existing on the high temperature end side. This is because the gas existing on the low temperature end side of the displacer 22 is cooled at the low temperature end of the regenerator 38 and the expansion space 28.

  The expander 13 according to the embodiment may be installed in a direction in which the longitudinal axis of the displacer 22 extends (direction of the reciprocating movement of the displacer 22) in the horizontal direction, that is, in a direction intersecting with gravity. In this case, since the low temperature gas is generally heavier than the high temperature gas, the low temperature gas moves to the lower part of the internal space of the displacer 22 and the convection occurs in which the high temperature gas moves to the upper part of the internal space. Thereby, a temperature gradient is generated in the gas filled in the inner space of the displacer 22 in a direction intersecting the longitudinal axis of the displacer 22. More specifically, among the gases filled in the inner space of the displacer 22, the gas present on the lower side with respect to gravity has a lower temperature than the gas present on the upper side.

  Hereinafter, the expander 13 according to the embodiment is based on the premise that the direction in which the longitudinal axis of the displacer 22 extends is the horizontal direction. For this reason, the direction of gravity is assumed to be a direction intersecting the longitudinal axis of the displacer 22.

  A temperature gradient is generated in the direction of gravity in the gas filled in the inner space of the displacer 22, so that a temperature gradient is also generated in the regenerator 38 surrounding the outer periphery of the displacer 22 in the direction of gravity. That is, the regenerator 38 that exists on the lower side with respect to gravity has a lower temperature than the regenerator 38 that exists on the upper side. The low temperature end of the regenerator 38 is in thermal contact with the low temperature heat exchanger 39 to exchange heat, but if the temperature of the low temperature end of the regenerator 38 differs depending on the location, heat loss occurs during heat exchange, The refrigeration performance of the Stirling refrigerator 10 is reduced.

  Therefore, the displacer 22 according to the embodiment accommodates one or a plurality of convection suppression plates 42 arranged in a direction intersecting the longitudinal axis of the displacer 22 in the internal space. Since the internal space of the displacer 22 is partitioned into a plurality of small rooms by the convection suppressing plate 42, the convection of gas in the entire internal space is suppressed. The convection suppression plate 42 is preferably arranged in a direction perpendicular to the longitudinal axis.

  The convection suppression plate 42 is preferably a member having a low emissivity and a high thermal conductivity. This can be realized by an aluminum plate, for example. The convection suppression plate 42 is preferably in airtight contact with the inner wall of the displacer 22. In addition, the regenerator 38 present on the lower side with respect to the gravity and the regenerator 38 present on the upper side are thermally connected via the wall of the displacer 22 and the convection suppression plate 42. For this reason, it is possible to reduce the occurrence of a temperature gradient in the direction of gravity in the regenerator 38.

  Drawing 3 (a)-(b) is a figure for explaining the accommodation position of convection control board 42 concerning an embodiment. More specifically, FIG. 3A is a diagram illustrating a state when the displacer 22 is at the bottom dead center, and FIG. 3B is a diagram illustrating a state when the displacer 22 is at the top dead center. .

  As shown in FIGS. 3A and 3B, the relative position of the convection suppression plate 42 with the regenerator 38 also changes as the displacer 22 reciprocates. 3 (a) and 3 (b), the convection suppression plate 42a accommodated in the vicinity of the middle of the accommodating space of the displacer 22 is “position corresponding to the regenerator 38” even if the displacer 22 reciprocates. Exists. On the other hand, in the accommodation space of the displacer 22, the convection suppression plate 42b accommodated on the higher temperature end side than the convection suppression plate 42a deviates from the “position corresponding to the regenerator 38” depending on the position of the displacer 22.

  For example, as shown in FIG. 3B, the convection suppression plate 42 b is present at “a position corresponding to the regenerator 38” when the displacer 22 is at the top dead center. However, as shown in FIG. 3 (a), when the displacer 22 is at bottom dead center, the convection suppression plate 42b deviates from the “position corresponding to the regenerator 38” and “corresponds to the water-cooled heat exchanger 37”. It will be “position to do”

  As described above, the regenerator 38 present on the lower side with respect to the gravity and the regenerator 38 present on the upper side are thermally connected via the convection suppression plate 42, so that the temperature of the regenerator 38 is increased in the direction of gravity. The occurrence of a gradient can be reduced. Therefore, it is preferable that the convection suppressing plate 42 is provided so as to be in a “position corresponding to the regenerator 38” even when the displacer 22 reciprocates. The convection suppression plate 42 is preferably housed in a position such as the convection suppression plate 42a instead of the position of the convection suppression plate 42b in FIGS. 3 (a) and 3 (b).

  Thus, by providing the convection suppression plate 42 in the internal space of the displacer 22, the convection of the gas filling the internal space can be reduced, and the occurrence of a gas temperature gradient in the direction of gravity can be reduced. As a result, a temperature gradient in the direction of gravity can be reduced in the regenerator 38. Furthermore, the regenerator 38 existing on the lower side and the regenerator 38 existing on the upper side are thermally connected via the convection suppressing plate 42. This also contributes to the reduction of the temperature gradient that occurs in the direction of gravity in the regenerator 38. Accordingly, the displacer 22 has a certain effect even if only one convection suppression plate 42 is provided, but the effect of suppressing the temperature gradient generated in the gravitational direction in the regenerator 38 is higher when a plurality of displacers 22 are provided as shown in FIG.

  By partitioning the internal space of the displacer 22 with one or a plurality of convection suppression plates 42, the convection of the gas filling the internal space can be reduced. However, even if the internal space of the displacer 22 is partitioned into a plurality of small rooms by the convection suppressing plate 42, gas is still present in each small room. For this reason, even if the internal space of the displacer 22 is partitioned by the convection suppressing plate 42, it is difficult to completely suppress the heat loss due to the convection of the gas. Further, the heat of the gas filling the internal space is conducted to the regenerator 38, so that the temperature of the regenerator 38 rises and heat loss may occur.

  Therefore, in addition to the convection suppression plate 42, the displacer 22 may accommodate a filling member that suppresses convection of gas in the internal space.

  FIG. 4 is a schematic diagram showing an internal configuration of the displacer 22 according to another embodiment. The displacer 22 shown in FIG. 4 accommodates a filling member 43 for suppressing gas convection in the internal space in addition to the convection suppressing plate 42. Here, the filling member 43 is held in the internal space by being sandwiched between the convection suppression plates 42. Hereinafter, portions overlapping with the internal configuration of the displacer 22 shown in FIG. 2 will be described by omitting or simplifying them as appropriate.

  As shown in FIG. 4, by filling the filling member 43 between two different convection suppression plates 42, the gas in the small room partitioned by the convection suppression plate 42 decreases. By reducing the gas itself, it is possible to suppress heat loss due to the convection of the gas.

  Here, the proportion of the filling member 43 in the internal space of the displacer 22 is larger than that of the convection suppressing plate 42. For this reason, in order to suppress an increase in the weight of the displacer 22, the filling member 43 is configured to have a small specific gravity. Specifically, the filling member 43 can be realized by using a fibrous or net-like member. In addition, since the inside of the displacer 22 may be at a low temperature of, for example, about 70K, the filling member 43 is made of a material that does not easily cause low-temperature brittle fracture. Specifically, the filling member 43 can be realized by using a resin such as a fluorine-based resin or an aramid resin, pumice, or the like. In order to suppress radiation, the filling member 43 may be attached with an aluminum tape on the surface or may be sputtered to deposit an aluminum film.

  The displacer 22 shown in FIG. 4 has a multi-layered structure in which a large number of filling members 43 are spread in contact with the convection suppression plate 42 and the inner wall of the displacer. Thus, by making the filling member 43 into a laminated structure, the heat conduction from the filling member 43 to the regenerator 38 can also be reduced.

  As described above, each of the one or more convection suppression plates 42 is a partition extending along a plane intersecting the longitudinal axis direction C of the displacer 22, preferably along a plane orthogonal to the longitudinal axis direction C. It is a plate. The partition plate divides the internal space of the displacer 22 into small rooms. Each of the small rooms may be airtight. This plate also serves as a thermal bridge that thermally bridges the interior space of the displacer 22. The partition plate forms a thermal bridge in the internal space of the displacer 22 from a side wall on one side of the displacer 22 in a direction intersecting the longitudinal axis direction C (for example, a gravitational direction). The gravity direction G is illustrated in FIG.

  The arrangement of the one or a plurality of convection suppression plates 42 can be various in particular in the position of the convection suppression plate 42 in the longitudinal axis direction C of the displacer 22 and the interval between the convection suppression plates 42. For example, as shown in FIGS. 3A and 3B, one of the two convection suppression plates 42 is located in the middle temperature portion of the displacer 22 and the other is located in the high temperature portion of the displacer 22. Further, as shown in FIGS. 2 and 4, the convection suppression plates 42 are arranged at equal intervals in the longitudinal axis direction C of the displacer 22. That is, the gaps between the convection suppression plates 42 have the same width in the longitudinal axis direction C.

  However, the convection suppression plate 42 may be arranged at a place different from the above-described embodiment. For example, the convection suppression plates 42 may be arranged at unequal intervals. As shown in FIG. 5, the convection suppression plates 42 may be arranged closely on the expansion space 28 side in the longitudinal axis direction C of the displacer 22. Therefore, the convection suppression plates 42 may be arranged sparsely on the gas space 36 side. The minimum interval of the convection suppressing plate 42 in the longitudinal axis direction C may be, for example, half or less of the maximum interval.

  The displacer 22 accommodates at least three (5 in FIG. 5) convection suppression plates 42 in the internal space. The convection suppression plate 42 includes a first plate located on the expansion space 28 side, a second plate located on the middle, and a third plate located on the gas space 36 side. These three partition plates are arranged adjacent to each other in the longitudinal axis direction C. A first small chamber is formed between the first plate and the second plate, and a second small chamber is formed between the second plate and the third plate.

  The width W1 of the first small room in the longitudinal axis direction C is narrower than the width W2 of the second small room. The distance between the first plate and another plate (or the tip of the displacer 22) adjacent to the first plate on the side of the expansion space 28 may be equal to or smaller than the width W1 of the first small chamber. Good. The distance between the third plate and another plate (or the proximal end portion of the displacer 22) adjacent to the third plate on the gas space 36 side may be equal to or wider than the width W2 of the second small chamber. Also good.

  Alternatively, the displacer 22 may accommodate two convection suppression plates 42 in the internal space. Contrary to the embodiment shown in FIGS. 3 (a) and 3 (b), one of the two convection suppression plates 42 is located in the middle temperature portion of the displacer 22 and the other is located in the low temperature portion of the displacer 22. May be. In this case, a first small chamber is formed between the first convection suppression plate 42 on the expansion space 28 side and the tip of the displacer 22, and a second small chamber is formed between the first and second convection suppression plates 42. The The width of the first small room in the longitudinal axis direction C is narrower than the width of the second small room.

  According to the embodiment shown in FIG. 5, the internal space of the displacer 22 can be finely divided in the longitudinal axis direction C on the expansion space 28 side. In this way, convection in the low temperature part can be more effectively suppressed. Thereby, the fall of the refrigerating performance by the convection of the gas in the displacer 22 can be suppressed.

  In particular, the low-temperature part has a small heat capacity, and is easily affected by convection such as a temperature rise caused by inflow of high-temperature gas. Further, the temperature gradient in the longitudinal axis direction C in the regenerator 38 of the Stirling refrigerator 10 shown in the figure is larger in the low temperature part than in the high temperature part (the temperature difference per unit length in the axial direction is lower than the high temperature end. large). Therefore, convection is more likely to occur in the low temperature part. Such a phenomenon can be dealt with by closely arranging the convection suppression plates 42 in the low temperature portion.

  In the first place, convection is caused by the attitude of the expander 13 of the Stirling refrigerator installed at the site, in particular, the horizontal placement of the expander 13 (installation with the longitudinal axis direction C as the horizontal direction). According to this embodiment, since the fall of the refrigerating performance by a convection is suppressed, a Stirling refrigerator can be installed not only horizontally but in an arbitrary posture.

  As described with reference to FIGS. 2 to 4, in the embodiment shown in FIG. 5, the convection suppression plate 42 is in the “position corresponding to the regenerator 38”. During the reciprocating motion of the displacer 22, the convection suppression plate 42 is always located in a cylindrical region surrounded by the regenerator 38. Alternatively, the at least one convection suppression plate 42 may be out of the “position corresponding to the regenerator 38”. The at least one convection suppression plate 42 may be located outside the cylindrical region in at least a part of the reciprocating motion of the displacer 22. For example, when the displacer 22 is at the top dead center, the convection suppressing plate 42 disposed adjacent to the tip of the displacer 22 (that is, located at the lowest temperature side) corresponds to “the low temperature heat exchanger 39 or the cooling stage 29. "Position".

  As the number of convection suppression plates 42 increases, the displacer 22 becomes heavier. When importance is attached to the weight reduction of the displacer 22, the convection suppression plate 42 may be provided only on the expansion space 28 side in the displacer 22. In this case, a relatively wide cavity is formed in the displacer 22 on the gas space 36 side. A filling member 43 may be accommodated in the cavity.

  In some embodiments, each of the convection suppression plates 42 may have an opening 44. The opening portion 44 of a certain convection suppression plate 42 has a first small chamber in the inner space of the displacer 22 adjacent to the first side of the convection suppression plate 42 and an inner space of the displacer 22 adjacent to the second side of the convection suppression plate 42. Communicating with the second small room. The opening 44 is a vent hole provided for facilitating evacuation of the displacer 22. The evacuation is performed, for example, in order to exhaust air from the inner space of the displacer 22 when the expander 13 of the Stirling refrigerator is manufactured. After evacuation, the inner space of the displacer 22 is filled with the working gas of the Stirling refrigerator. Such an opening 44 may be provided in at least one convection suppression plate 42.

  While the opening 44 is advantageous for manufacturing the expander 13, it can provide a gas convection path between the small chambers when the expander 13 is used. This is especially true when the openings 44 of the convection suppression plates 42 are aligned.

  Therefore, as shown in FIG. 6, at least one convection suppression plate 42 may include a convection suppression wall 46 provided in the opening 44. Each convection suppression plate 42 has an opening 44 at the center thereof. The convection suppression wall 46 extends from the outer periphery of the opening 44 to both sides in the axial direction of the convection suppression plate 42. The convection suppression wall 46 may extend from the opening 44 to one side in the axial direction. In this way, the side wall surrounding the opening 44 extends discontinuously along the central axis of the displacer 22. When the opening 44 is circular, the convection suppression wall 46 is a cylinder. The axial gap D between a certain convection suppression wall 46 and the convection suppression wall 46 adjacent thereto is, for example, in the range of 1/4 to 3/4 of the axial interval W of the convection suppression plate 42, for example, about 1/2. It is. In this way, by adding a side wall to the opening 44, gas convection between the small rooms through the opening 44 can be effectively suppressed.

  Instead of the convection suppression wall 46, as shown in FIG. 7, adjacent openings 44 may be formed at different locations. That is, the opening 44 of a certain convection suppression plate 42 and the opening 44 of another convection suppression plate 42 adjacent thereto are different from each other in a plane that intersects the longitudinal axis of the displacer 22 (for example, a plane orthogonal to the longitudinal axis). It may be located at a place. Even if it does in this way, the gas convection between the small rooms through the opening part 44 can be suppressed effectively. Such an offset arrangement of the openings 44 is particularly effective when the convection suppression plates 42 are closely arranged in the axial direction as in the embodiment described with reference to FIG. In some embodiments, a combination of the offset arrangement of the opening 44 and the convection suppression wall 46 may be used.

  As described above, according to the Stirling refrigerator 10 of the present invention, gas convection in the displacer 22 can be more appropriately suppressed. Thereby, the fall of the refrigerating performance by the convection of the gas in the displacer 22 can also be suppressed.

  In the above, this invention was demonstrated based on the Example. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiment, and various design changes are possible, various modifications are possible, and such modifications are within the scope of the present invention. By the way.

  DESCRIPTION OF SYMBOLS 10 Stirling refrigerator, 11 compressor, 12 connection pipe, 13 expansion machine, 14 compressor case, 15 movable member, 16 support part, 20 expansion machine main body, 22 displacer, 24 1st division, 25 seal part, 26 2nd Partition, 28 expansion space, 29 cooling stage, 30 elastic member, 32 displacer body, 34 displacer rod, 36 gas space, 37 water-cooled heat exchanger, 38 regenerator, 39 low-temperature heat exchanger, 40 support, 42 convection suppression Plate, 43 filling member, 44 opening, 46 convection suppression wall.

Claims (11)

A displacer having an interior space filled with gas;
An expander body that accommodates the displacer in a reciprocating manner;
The displacer houses one or more convection suppression plates that suppress the convection of the gas in the internal space,
The Stirling refrigerator, wherein the convection suppressing plate is disposed in a direction intersecting with a longitudinal axis of the displacer. The regenerator further includes a regenerator provided in the expander main body so as to be located in a predetermined cylindrical region centering on the longitudinal axis of the displacer at the outer periphery of the displacer,
2. The Stirling refrigerator according to claim 1, wherein the convection suppression plate is provided so as to be in a position corresponding to a predetermined region where the regenerator is located even when the displacer reciprocates.   The Stirling refrigerator according to claim 1, wherein the displacer includes a plurality of convection suppression plates.   The Stirling refrigerator according to any one of claims 1 to 3, wherein the convection suppression plate is in thermal contact with an inner wall of the displacer. The displacer further includes a filling member that suppresses convection of the gas,
The Stirling refrigerator according to any one of claims 1 to 4, wherein the convection suppressing plate holds the filling member.   The Stirling refrigerator according to claim 5, wherein the filling member is made of resin.   The Stirling refrigerator according to claim 5 or 6, wherein the filling member is a fibrous or net-like member. The expander body forms an expansion space with the displacer, forms a compression space with the displacer on the opposite side of the expansion space in the direction of the longitudinal axis of the displacer,
The displacer accommodates, in the internal space, a plurality of convection suppression plates arranged densely on the expansion space side and sparsely on the compression space side in the longitudinal axis direction of the displacer. To Stirling refrigerator in any one of 7.   At least one convection suppression plate communicates the first small chamber of the internal space adjacent to the first side of the convection suppression plate with the second small chamber of the internal space adjacent to the second side of the convection suppression plate. The Stirling refrigerator according to claim 1, further comprising an opening.   The Stirling refrigerator according to claim 9, wherein the at least one convection suppression plate includes a convection suppression wall provided in the opening.   The opening part of a certain convection suppression board and the opening part of another convection suppression board adjacent to it are located in a mutually different place in the plane which cross | intersects the longitudinal axis of the said displacer. Stirling refrigerator.

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